Airbus Industries - measuring the centre of gravity in the production of Airbus models A320, A330 and A340

Airbus Industries represents four European aircraft manufacturers that are at the forefront of global competition. With the Airbus A320, A330 and A340-600 models Airbus Industrie offers a winning range of aircraft for the fiercely competitive global market. Aerospatiale Toulouse is the partner with the task of final assembly.

Airbus Industrie represents four European aircraft manufacturers that are at the forefront of global competition. With the Airbus A320, A330 and A340-600 models Airbus Industrie offers a winning range of aircraft for the fiercely competitive global market. Aerospatiale Toulouse is the partner with the task of final assembly.

Once an aircraft has been assembled its centre of gravity must be determined with the utmost precision. Until now, this has been done using existing mechanical systems. However, these old systems can no longer keep up with demands for greater accuracy and mobile use. The aim was therefore to use reliable state-of-the-art measurement technology to measure the overall centre of gravity and the effective contact forces on all these Airbus models with the greatest possible precision.

The general problems here are the very flexible structure of an aircraft and the fact that lateral forces greater than 10% can occur in the longitudinal and transverse axes. A further complicating factor is that there is very little space available for the measuring instrument.

In highly detailed comparison tests under real conditions the HBM series C4 force transducer put in a convincing performance despite the difficult framework conditions. Linearity and reproducibility in different installation positions were of particular interest. The C4 was able to far exceed expectations in all respects.

Nonetheless, preliminary tests gave rise to the wish to optimise the results still further with recognition of the lateral forces in the x and y axes. HBM is able to draw on decades of know-how in the construction of force transducers and other equipment, and utilises this knowledge for standard transducers and in particular for customer-specific transducers – some of which for extreme requirements. In this case the requirement could be met by customising the standard transducer specifically for the customer with double bridges and external x and y channels.

The measurement equipment is rounded off with what is still the most accurate measuring system for strain gauge transducers, the DMP40. This system provides measurement signal resolutions up to the limit of the component noise.

The follow-up tests were all very successful, such that further measurement systems are being realised for this application. The solution found using HBM’s measurement technology puts in a persuasive performance by combining clever technology with simplicity of use. These advantages – coupled with precision and reliability – certainly pay off, as evidenced by a cost comparison: the new solution costs much less. It also forms a good reference solution from HBM for the worldwide use of such systems.